Restricted characters in element names and vocabulary labels

XSD element names must respect Java identifier conventions, but vocabulary labels are less restricted.

The restrictions on XSD element names and vocabulary labels are not the same. The restrictions on vocabulary labels must be respected when customizing default verbalization.

Element name restrictions

Because the XSD is transformed into a BOM, Java identifier conventions apply to all XSD element names.

An element name must not have any of the following characteristics:
  • Be empty

  • Be longer than 255 characters

  • Start or end with white space characters

  • Contain the characters ",.,:,*,/,<,>,?,\, or |

  • Contain a character that has an ASCII or Unicode code below 0x1f, included

Vocabulary label restrictions

Vocabulary labels, which are used for verbalization, are less restricted than element names, but certain characters create ambiguity and confusion.

Avoid these characters: ' < > " ( ) { }

Numeric values can also cause confusion in vocabulary labels. When possible, do not use digits in verbalizations.

  • If you must use digits, avoid space and comma separators between the digits, especially if those characters are valid group delimiters or decimal markers in the locale of the vocabulary.
  • If you must use space or comma separators in your verbalization, surround the full number with double quotation marks, for example, "3,14159265".